diff options
| author | Damien George <damien@micropython.org> | 2025-06-12 10:52:32 +1000 |
|---|---|---|
| committer | Damien George <damien@micropython.org> | 2025-06-14 01:06:27 +1000 |
| commit | fa393feaed16eb040c3fa7f57537eca1404f6f70 (patch) | |
| tree | d1e5923fe664bfbd0dc4444d8a55af28205efb71 /ports | |
| parent | 6201e77999b3614518abc4b21773e735d9b0b0ee (diff) | |
| download | micropython-master.tar.gz micropython-master.zip | |
Signed-off-by: Damien George <damien@micropython.org>
Diffstat (limited to 'ports')
| -rw-r--r-- | ports/esp32/README.md | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/ports/esp32/README.md b/ports/esp32/README.md index e11c64ad70..d8b55e45f3 100644 --- a/ports/esp32/README.md +++ b/ports/esp32/README.md @@ -221,6 +221,30 @@ import machine antenna = machine.Pin(16, machine.Pin.OUT, value=0) ``` +Partition table and filesystem size +----------------------------------- + +ESP32 firmware contains a bootloader, partition table and main application +firmware, which are all stored in (external) SPI flash. The user filesystem +is also stored in the same SPI flash. By default, MicroPython does not have +a fixed entry in the ESP32 partition table for the filesystem. Instead it +will automatically determine the size of the SPI flash upon boot, and then -- +so long as there is no existing partition called "vfs" or "ffat" -- it will +create a partition for the filesystem called "vfs" which takes all of the +remaining flash between the end of the last defined partition up until the +end of flash. + +This means that firmware built for, say, a 4MiB flash will work on any +device that has at least 4MiB flash. The user "vfs" filesystem will then +take up as much space as possible. + +This auto-detection behaviour can be overridden: if the ESP32 partition +table does contain an entry called "vfs" or "ffat" then these are used for +the user filesystem and no automatic "vfs" partition is added. This is +useful in cases where only the MicroPython ESP32 application is flashed to +the device (and not the bootloader or partition table), eg when deploying +.uf2 files. + Defining a custom ESP32 board ----------------------------- |